1. Field of the Invention
The present invention relates to a control apparatus for a machine tool capable of positioning a tool support to a start position with high accuracy.
2. Description of the Prior Art
In the past, the return of a movable member, such as a wheel support, in a grinding machine to a start position has been performed by using as a reference position a start position and by actuating a limit switch which is fixed to the bed of the grinding machine by the wheel support. A disadvantage with the prior art arrangement is that because the start position is fixed to the bed the distance between a workpiece and a grinding wheel on the wheel support retracted to the start position cannot be changed easily in accordance with the change in the diameter of a workpiece to be ground.
Furthermore, the wheel support cannot be positioned at the start position with high accuracy because of operation error of the limit switch.